1. Field of the Invention
The invention relates to a drilling fluid pump and conditioner. More specifically, the invention relates to a unitary device capable of accepting drilling fluids containing barite, bentonite, dissolved gases and drilled solids from a subterranean well and simultaneously pumping and segregating the above components.
2. Description of the Prior Art
Drilling fluids are used to cool and lubricate a working drill bit, carry away cuttings formed beneath the bit, and cleanse the bottom of the bore hole of such cuttings. Generally, the drilling fluids contain a number of components which aid in preventing well blowouts, lend viscosity properties to the drilling fluid, lower the filter loss of the liquid component into a permeable subterranean formation and serve similar advantageous functions.
Most drilling fluids contain three major components when they are circulated out of the well. These components are barite, bentonite, and drilled solids or cuttings along with some amounts of dissolved well gases. Barite is used as a weighting agent to prevent blowouts of the well, while bentonite is used, along with other valuable recoverable chemicals, to impart viscosity and filtration properties to the drilling fluid. It is desirable to recover the barite and bentonite fractions of the drilling fluid while disposing of the drilled chips or cuttings so that the drilling fluid can be recycled at the well site. Additionally, it is occasionally advantageous to segregate and recover dissolved well gases.
Presently, there are a number of known methods used to attempt to separate the valuable portions of drilling fluid circulated out of a well from the undesirable drilled solids such as clay, sand, siliceous material, and other fragmented portions of the subterranean structure being drilled through. One such system accepts the drilling fluid from a well, screens the drilling fluid to exclude large fragmentary portions, and cycles the remaining fluid to a separator. The separator, on the initial pass therethrough of the fluid, removes heavy solids from the fluid and cycles the remaining fluid to a holding tank. After one cycle is completed, the fluid collected in the holding tank is cycled through the separator thereby separating intermediate and low density particles which are separately collected and treated. Such systems require substantial investment in holding tanks, valving systems, piping, process control electronics and similar associated devices. This expense is a detriment to the usefulness of such systems.
Similarly, in the past, attempts have been made to use centrifuges to separate drilling fluids into solid and liquid portions, with a part of the solid material being returned to the drilling fluid. These attempts have not been altogether successful owing to the somewhat thixotrophic characteristic of the drilling fluid which substantially retard normal centrifugation.
Fluocculation methods have also been used to separate certain solids from the drilling fluid. Again, the somewhat thixotrophic nature of conventional aqueous or invert drilling fluids interferes with fluocculation methods of separating solids. Additionally, large amounts of fluocculants are used in such procedures, increasing the cost of the methods. Therefore, there is a need in the market place for a simple, reliable method of separating components of drilling fluids without the use of costly centrifugation and fluocculation methods or the use of multiple passes through a single particle separator.